Introduction
Tracheobronchial tuberculosis (TBTB) is tuberculosis that occurs in the mucosa, submucosa, smooth muscle, cartilage, and outer lining of the trachea and bronchi. The diagnosis of tracheobronchial tuberculosis still relies on bronchoscopic examination and bacteriological or pathological evidence. Wang Xiaoping, Department of Respiratory Medicine, Shandong Provincial Chest Hospital
Before starting the article, let me correct you: it is strictly wrong to call “tracheobronchial tuberculosis” as “endobronchial tuberculosis”. Endobronchial tuberculosis refers to the invasion of the mucous membrane of the trachea and bronchi that can be directly observed under tracheoscopy, and because clinically there are more bronchial lesions than tracheal lesions, it used to be called endobronchial tuberculosis (EBTB). With increased awareness, it has been found that tuberculosis can invade parts of the bronchus other than the mucosa, so the term endobronchial tuberculosis is less appropriate.
Based on the main gross changes and histopathological features observed on bronchoscopy, the following types are distinguished: inflammatory infiltrative, ulcerative necrotic, granuloproliferative, scar stenosis, wall softening, and lymph node fistula. In this issue, we will first look at the ulcerative necrotic type.
Ulcerative necrotic type: The lesions are mainly localized ulcers and necrosis. The ulcer depth varies with the severity of the lesion, the lighter ones are limited to the mucosal layer, the heavier ones can even lead to the destruction of tracheal and bronchial cartilage, and the lesion area can bleed easily when touched. This type has a high rate of detection of antacid bacilli and is the obvious stage of tuberculosis lesion damage.
Ulcerated necrotic type (less severe microscopic manifestation).
Ulcerated necrotic type (heavier microscopic manifestation).
Based on the main gross changes and histopathological features observed under bronchoscopy, the following types are classified: inflammatory infiltrative, ulcerative necrotic, granulomatous proliferative, scar stenosis, wall softening, and lymph node fistula.
Inflammatory infiltrative type of tracheobronchial tuberculosis
Type I (inflammatory infiltrative type): The lesions are mainly congested and edematous. The lesions are characterized by congestion and edema of the tracheal and bronchial mucosa, grayish white corn-like nodules on the local mucosal surface, and swelling of the submucosal tissue of the airway with varying degrees of narrowing. This type has a high rate of detection of antacid bacilli in brush smears at the bronchial mucosa, and biopsies show a predominantly inflammatory cell infiltration in the bronchial tissue, which is an early histological change of tuberculosis lesion. From the 2012 edition of the “Guidelines for the diagnosis and treatment of tracheobronchial tuberculosis (Trial)
Tracheoscopic presentation.
The above picture shows that the mucous membrane in the patient’s left main bronchus is congested and gray-white corn-like nodules are seen on the surface, which belongs to the inflammatory infiltrative type. The microscopic manifestation of tracheobronchial tuberculosis can combine one or more manifestations, especially for the four types: inflammatory infiltrative, ulcerative necrotic, granulomatous proliferative, and scar stenosis, and there are often more cases of the combination of the two types in clinical practice. For example, in the above picture, the patient had a mild lesion in the left main bronchus, which was of the inflammatory infiltrative type. As the bronchoscope continued to go deeper and reached the opening of the bronchus in the upper lobe of the left lung, a large amount of white cheese material could be seen in the wall of the tube, which was of the ulcerative necrotic type (see the picture below).
Based on the main gross changes and histopathological features observed under bronchoscopy, the following types were classified: inflammatory infiltrative, ulcerative necrotic, granulomatous proliferative, scar stenosis, wall softening, and lymph node fistula.
Granuloproliferative type of tracheobronchial tuberculosis
Type III (granuloproliferative type): The lesion is mainly proliferation of local granulation tissue. The congestion and edema of tracheal and bronchial mucosa are reduced, and the ulcerated surface of the mucosa begins to repair, and granulation tissue proliferation can be seen in obvious places of the lesion, and necrotic material can be seen on the surface, and the proliferating granulation tissue partially blocks the lumen. At this point, the histological changes are in the transitional stage from the damage to the repair phase of the tuberculosis lesion, and biopsies often show more typical epithelioid cells, multinucleated giant cells and Langhans giant cells. From the 2012 edition of the Guidelines for the diagnosis and treatment of tracheobronchial tuberculosis (Trial)
Tracheoscopic manifestations of bronchial tuberculosis (granuloproliferative type) 1: Massive granulomatous tissue proliferation is seen in the lumen.
Tracheoscopic manifestation of bronchial tuberculosis (granuloproliferative type) 2: The following picture also belongs to the predominantly granuloproliferative type, combined with ulcerative necrosis. A small amount of caseous material can be seen on the surface of the trachea, and granulation tissue is attached under the caseous material, and the proliferating granulation tissue is tough and has strong adhesion to the wall of the tube.
(To be continued)